Composite muffler system thermosetable polymers

ABSTRACT

A muffler assembly includes a housing defining at least one internal chamber. The housing is constructed from a composite material made from a thermoplastic resin and a reinforcing element. The reinforcing element is selected from a group of reinforcing materials consisting of glass fibers, aramid fibers, polyamide fibers, carbon fibers, graphite fibers, mineral fibers, ceramic fibers, carbon nanotubes, nano fillers, mineral fillers, ceramic fillers and combinations thereof. A pipe is received in the housing. The pipe includes at least one opening providing acoustic communication between an internal passage in the pipe and the chamber in the housing. An acoustic attenuating material is received in that chamber.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY

This invention relates generally to a muffler assembly and, more particularly, to a muffler assembly made from a composite material.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 5,726,398 to Zahn et al discloses a bumper/muffler assembly. A portion of the structure defining the muffler also forms part of the bumper and, hence, must be capable of absorbing high impact loads. If, after a certain period of vehicle operation, the muffler becomes defective and must be replaced, those defective parts must be replaced with costly parts capable of performing dual functions: that is, the attenuation of acoustic energy and the absorption of high impact loads. The '398 patent also teaches that the bumper/muffler assembly may be formed from metal. There are inherent limitations from a design standpoint regarding possible shapes and sizes for metal mufflers. Hence, the ability to design mufflers capable of being received in irregularly shaped vehicle recesses or cavities is restricted. It is also noted that tooling costs for metal mufflers is very high, which is problematic where only a limited number of mufflers are to be produced for any particular vehicle application or model.

U.S. Pat. No. 6,668,972 to Huff et al discloses a bumper/muffler assembly including an outer housing or shell formed from a metal, a resin or a composite material. The composite material is described as comprising reinforcement fibers and a resin material. The resin material is then further identified as a phenolic resin, including but not limited to phenol formaldehyde resins such as novolac and resole resins, epoxy resins, vinyl ester resins, polyphenylene sulfide, high temperature nylons and polyetheretherketone. The reinforcement fibers are described as glass fibers, graphite fibers, aramid fibers, carbon fibers, metallic fibers and/or ceramic fibers.

The present invention relates to a new and improved muffler assembly incorporating a housing made from composite material wherein at least a portion of that housing may be molded or made so as to form a vehicle component and thereby perform a dual function.

SUMMARY OF THE INVENTION

In accordance with the purposes of the present invention as described herein, a muffler assembly is provided. That muffler assembly comprises a housing defining at least one internal chamber. The housing is constructed from a composite material made from a thermoplastic resin and a reinforcing element. The reinforcing element is selected from a group of reinforcing materials consisting of glass fibers, aramid fibers, polyamide fibers, carbon fibers, graphite fibers, mineral fibers, ceramic fibers, carbon nanotubes, nano fillers, mineral fillers, ceramic fillers and combinations thereof. The muffler assembly also includes a pipe that is received in the housing. The pipe includes at least one opening providing acoustic communication between an internal passage in the pipe and the chamber in the housing. Still further, the muffler assembly includes acoustic attenuating material received in the chamber in the housing.

The thermoplastic resin utilized to form the composite material is selected from a group of resin materials consisting of polyamide, nylon 6, nylon 66, nylon 46, aromatic polyamide, polyetherimide, polyethersulfone, polysulfone, polyphthalamide, polyphenylene sulfide, syndiotactic polystyrene, polyetherimide/silicone blend, liquid crystal polymer, polybutylene terephthalate, polyethylene terephthalate, cyclic thermoplastic, macrocyclic butylenes terephthalate, macrocyclic ethylene terephthalate, macrocyclic polycarbonate, thermoplastic urethane, polytetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone and combinations thereof.

In one possible embodiment the composite material comprises a glass reinforcing element with a glass fiber weight fraction ranging from about 5 to about 90 weight percent where greater than about 5 weight percent of said glass fiber fraction has an original length to diameter ratio of greater than or equal to 50.

In yet another possible embodiment the composite material is a mixture of between about 0 and about 90 weight percent polypropylene, between about 0 and about 90 weight percent polyethylene terephthalate and between about 10 and about 85 weight percent glass fibers.

In any of the embodiments, the composite material may also include some thermoset resin. That thermoset resin may be selected from a group of thermoset resins consisting of unsaturated polyester, dicyclopentadiene, phenolic, phenol formaldehyde, novalac, resol, epoxy, vinyl ester, urethane and combinations thereof.

Still further describing the invention, the housing may include an inlet and an outlet. A first heat sink may be provided in the inlet and a second heat sink may be provided in the outlet. In addition, the housing may include an overmolded reinforcement. That overmolded reinforcement may be an inlay constructed from a material selected from a group consisting of nonwoven fiber mat, woven fiber mat, unidirectional fiber fabric, metal sheeting and combinations thereof. More specifically, the inlay may be made from a material consisting of glass fibers, natural fibers, carbon fibers, mineral fibers, metallic fibers, aramid fibers and combinations thereof.

In yet another embodiment, the overmolded reinforcement is an overlay providing impact resistance. The overlay may be constructed from a material including metal sheeting, steel, aluminum, stainless steel, woven fiber mat, unwoven fiber mat, unidirectional fiber fabric and combinations thereof.

Still further, the muffler assembly may include a baffle in the housing. The muffler assembly may also include a mounting bracket carried by the housing. Still further, the muffler may include an active sound control device carried by the housing. The housing may include a first section, a second section and a part line. The part line may run through the inlet and the outlet defined by the housing.

In accordance with additional aspects of the present invention at least a portion of the housing may form a vehicle body or chassis component. Thus, the composite material functions not only as the housing for the muffler but also forms a portion of the vehicle. The vehicle component formed by the housing may be selected from a group consisting of a spare wheel well, an underbody shield, a fender, a wheel arch, a bumper, a running board, a rocker panel, a side fairing and an air dam.

In accordance with still another embodiment of the invention, the muffler assembly may include an inner housing that is received in the housing. The inner housing may be constructed from a second composite material comprising a thermoset resin and a reinforcement element.

In the following description there is shown and described several preferred embodiments of this invention, simply by way of illustration of some of the modes best suited to carry out the invention. As it will be realized, the invention is capable of other different embodiments, and its several details are capable of modification in various, obvious aspects, all without departing from the invention. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of the specification, illustrates several aspects of the present invention, and together with the description serve to explain certain principles of the invention. In the drawings:

FIG. 1 is an exploded, perspective view of a muffler assembly constructed in accordance with a first embodiment of the present invention;

FIG. 2 is a detailed cross-sectional view illustrating the heat sink used in the first embodiment at the inlet end of the housing;

FIG. 3 is a view similar to FIG. 2 but illustrating an alternative second embodiment for the heat sink and the construction of the housing;

FIG. 4 is an exploded, perspective view of a second alternative embodiment of the invention illustrating a muffler assembly with a housing that also forms a vehicle bumper;

FIG. 5 is a perspective view illustrating yet another embodiment of the present invention wherein the muffler assembly forms a part of the spare wheel well;

FIG. 5 a is an exploded perspective view of still another embodiment wherein the housing of the muffler assembly forms part of the wheel well and the underbody shielding of the vehicle; and

FIG. 6 is a perspective view illustrating a muffler assembly forming, alternatively, part of a side fairing and running board or rocker panel of a truck.

Reference will now be made in detail to the present preferred embodiment of the invention an example of which is illustrated in the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Reference is now made to FIG. 1 illustrating a first embodiment of the muffler assembly 10 of the present invention. The muffler assembly 10 includes a housing 12 including a first section or shell 14 and a second section or shell 16. Each section 14, 16 includes a connection flange 18 that are put in abutting relationship to close the housing 12. The two sections 14, 16 may be secured together by any appropriate means known in the art including but not limited to ultrasonic welding and mechanical fasteners. As illustrated, the housing 12 includes an inlet 20 and an outlet 22. The parting line defined by the abutting flanges 18 runs through the inlet 20 and outlet 22 in the FIG. 1 embodiment. It should be appreciated, however, that the parting line is not required to run through the inlet 20 or the outlet 22.

An internal cavity or chamber 24 is defined by the housing 12. A pipe 26 is received in the housing 12. More particularly, in the illustrated embodiment the pipe 26 extends through the inlet 20, includes an intermediate section 28 that passes through the housing 12 and extends through the outlet 22. The intermediate section 28 of the pipe 26 includes a number of apertures or openings 30. These openings 30 provide acoustic communication between an internal passage in the pipe 26 and the internal chamber 24 formed by the housing 12. An acoustic attenuating material 32 is received in the chamber 24 in the housing 12 and serves to reduce the exhaust noise produced by the vehicle.

Heat sinks 34 are provided between the pipe 26 and the housing sections 14, 16 at the inlet 20 and outlet 22 in order to protect the housing sections 14, 16 from damage due to high temperatures. The housing 12 is constructed from a composite material made from a thermoplastic resin and a reinforcing element. The thermoplastic resin is selected from a group of resin materials consisting of polyamide, nylon 6, nylon 66, nylon 46, aromatic polyamide, polyetherimide, polyethersulfone, polysulfone, polyphthalamide, polyphenylene sulfide, syndiotactic polystyrene, polyetherimide/silicone blend, liquid crystal polymer, polybutylene terephthalate, polyethylene terephthalate, cyclic thermoplastic, macrocyclic butylenes terephthalate, macrocyclic ethylene terephthalate, macrocyclic polycarbonate, thermoplastic urethane, polytetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone and combinations thereof. The reinforcing element is selected from a group of reinforcing materials consisting of glass fibers, aramid fibers, polyamide fibers, carbon fibers, graphite fibers, mineral fibers, ceramic fibers, carbon nanotubes, nano fillers, mineral fillers, ceramic fillers and combinations thereof.

In one particularly useful embodiment the composite material comprises a long fiber thermoplastic including a thermoplastic resin selected from a group of thermoplastic resins consisting of nylon 6, nylon 66, nylon 46, aromatic polyamide, polyetherimide, polyethersulfone, polysulfone, polyphthalamide, polyphenylene sulfide, syndiotactic polystyrene, polyetherimide/silicone blend, liquid crystal polymer, polybutylene terephthalate, polyethylene terephthalate, cyclic thermoplastic, macrocyclic butylenes terephthalate, macrocyclic ethylene terephthalate, macrocyclic polycarbonate, thermoplastic urethane, polytetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone and combinations thereof. The long fiber thermoplastic also includes a glass reinforcing element with a glass fiber weight fraction ranging from about 5 to about 90 weight percent. Greater than about 5 weight percent of the glass fiber fraction has an original length to diameter ratio of greater than or equal to 50.

In yet another particularly useful embodiment of the present invention the composite material is a mixture of between about 0 and about 90 weight percent polypropylene, between about 0 and about 90 weight percent polyethylene terephthalate and between about 10 and about 85 weight percent glass fibers. In any of the possible embodiments the composite material may also include some thermoset resin. That thermoset resin is selected from a group of thermoset resins consisting of unsaturated poly, dicyclopentadiene, phenolic, phenol formaldehyde, novalac, resols, epoxy, vinyl ester, urethane and combinations thereof. The thermoset resin may comprise anywhere from about 5 to about 85 weight percent of the total resin in the composite material.

Reference is now made to FIG. 2 illustrating in detail the muffler assembly 10 of FIG. 1 but incorporating additional optional features. As illustrated in FIG. 2, the muffler assembly 10 includes a mounting bracket 38. A first end 40 of the mounting bracket 38 is molded into the composite material forming the housing 12. A second end 42 of the bracket 38 projects from the housing 12 and includes apertures 44 to receive fasteners (not shown) for mounting the muffler assembly 10 to a vehicle.

The muffler assembly 10 illustrated in FIG. 10 also includes a baffle 46 that divides the interior of the housing 12 into multiple chambers 24′ and 24″. While one baffle 46 is shown, it should be appreciated that multiple baffles 46 may be provided if desired. Acoustic attenuating material 32 such as continuous glass filament strands texturized with pressurized air and sold under the trademark SILENTEX may be received in each of the chambers 24′, 24″. The baffle 46 may also support an optional active sound control device 48. The active sound control device 48 comprises a sound cancellation generator including a controller, a sound sensor and a sound transducer. The sound control device 48 functions to produce a sound wave that partially or completely cancels sound generated by the exhaust gases passing through the vehicle exhaust system.

In accordance with an additional aspect of the present invention, the muffler assembly 10 may include an optional inlay 50. The inlay 50 may be made from a material selected from a group consisting of glass fibers, natural fibers, carbon fibers, mineral fibers, metallic fibers, aramid fibers and combinations thereof. Further, the inlay 50 may be overmolded with the composite material utilized to make the housing 12. Advantageously, the inlay 50 may be used to provide the housing 12 with extra strength such as, for example, for spanning the space between attachment points to the vehicle.

As further illustrated in FIG. 2, the muffler assembly 10 may also include an overlay 52. Such an overlay may be constructed, for example, from a material including metal sheeting, steel, aluminum, stainless steel, woven fiber mat, unwoven fiber mat, unidirectional fiber fabric and combinations thereof. The overlay 52 may be an overmolded reinforcement covered with the composite material that forms the shell 12. Typically, such an overlay 52 is provided along surfaces of the muffler assembly 10 that are exposed to potential impact damage such as from rocks or other debris that might be thrown up from the roadway.

Still another embodiment of the present invention is illustrated in FIG. 3. In this embodiment the muffler assembly 10 again includes a housing 10 forming a chamber 24 that again receives acoustic attenuating material 32. As previously described, the housing 10 also includes an inlet 20 lined with a heat sink 34. An exhaust pipe 26 passes through the inlet 20 with an intermediate section 28 of the pipe received in the chamber 24. Apertures 30 in the intermediate section 28 allow acoustic communication between the interior passageway or lumen of the pipe 26 and the chamber 24. In the illustrated embodiment the pipe 26 also includes a flex pipe section 27 that is partially received in the heat sink 34.

The embodiment illustrated in FIG. 3 also includes an inner housing 54 received as a lining of the housing 12. The inner housing 54 may be constructed from a second composite material comprising a thermoset resin and a reinforcement element. The thermoset resin may comprise unsaturated polyester, dicyclopentadiene, phenolic, phenol formaldehyde, novalac, resol, epoxy, vinyl ester, urethane and combinations thereof. The reinforcement element may comprise, for example, glass fibers, aramid fibers, polyamide fibers, carbon fibers, graphite fibers, mineral fibers, ceramic fibers, carbon nanotubes, nano fillers, mineral fillers, ceramic fillers and combinations thereof.

In accordance with an additional aspect of the present invention, since the housing 12 is molded or otherwise made from a composite material, it may easily be formed into intricate shapes. Accordingly, the housing 12 or at least a portion thereof may serve the dual function of providing a housing for the muffler assembly and also forming a body or chassis component of the vehicle such as a spare wheel well, an underbody shield, a fender, a wheel arch, a bumper, a running board, a rocker panel, a side fairing and an air dam.

Reference is now made to FIG. 4 illustrating yet another embodiment of the present invention wherein the muffler assembly 10 forms a bumper for the vehicle. More specifically, the first section 14 of the housing 12 forms the face and upper portion of the bumper. As illustrated, the first housing section 14 includes portions of the inlet 20, a portion of the outlet 22 and a portion of the chamber 24. The second section 16 of the housing 12 forms the bottom of the bumper and also includes portions of the inlet 20, outlet 22 and chamber 24. A pipe 26 including an intermediate section 28 with openings 30 is received in the housing 12. Heat sinks 34 are provided between the pipe and the inlet 20 and outlet 22. Acoustic attenuating material 32 is provided in the chamber 24 around the intermediate pipe section 28.

FIGS. 5 and 5 a illustrate yet another embodiment of muffler assembly 10 of the present invention. In this embodiment, the first section 14 of the housing 12 forms the spare wheel well. Thus, the first section 14 includes a cavity 60 for receiving the spare wheel. A cover 62 may be provided for closing the cavity. The second section 16 of the housing 12 forms the chamber 24 that receives the intermediate 28 of the pipe 26 as well as the sound attenuating material 32. A bumper plate closeout panel 64 including a tailgate seal 66, a composite bumper beam 68 and a fascia 70 complete the assembly. As illustrated in FIG. 5 a, the spare wheel well portion of the muffler assembly 10 may simply form a portion of an entire underbody shield and including wheel wells. That system of panels includes underbody panels, 72, 74 and 76 wherein a portion of the pipe 26 are sandwiched and received between the panels 74 and 76.

In yet another embodiment illustrated in FIG. 6, the muffler assembly 10 may incorporate a housing 12 that forms a part of the side fairing, air dam, running board or rocker panel of a truck T.

The foregoing description of the preferred embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. The drawings and preferred embodiments do not and are not intended to limit the ordinary meaning of the claims in their fair and broad interpretation in any way. 

1. A muffler assembly (10), comprising: a housing (12) defining at least one internal chamber (24), said housing being constructed from a composite material made from a thermoplastic resin and a reinforcing element selected from group of reinforcing materials consisting of glass fibers, aramid fibers, polyamide fibers, carbon fibers, graphite fibers, mineral fibers, ceramic fibers, carbon nanotubes, nano fillers, mineral fillers, ceramic fillers and combinations thereof; a pipe (26) received in said housing, said pipe including at least one opening (30) providing acoustic communication between an internal passage in said pipe and said at least one chamber; and acoustic attenuating material (32) received in said at least one chamber.
 2. The muffler assembly of claim 1, wherein said thermoplastic resin is selected from a group of resin materials consisting of polyamide, nylon 6, nylon 66, nylon 46, aromatic polyamide, polyetherimide, polyethersulfone, polysulfone, polyphthalamide, polyphenylene sulfide, syndiotactic polystyrene, polyetherimide/silicone blend, liquid crystal polymer, polybutylene terephthalate, polyethylene terephthalate, cyclic thermoplastic, macrocyclic butylenes terephthalate, macrocyclic ethylene terephthalate, macrocyclic polycarbonate, thermoplastic urethane, polytetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone and combinations thereof.
 3. The muffler assembly of claim 1, wherein said composite material comprises a long fiber thermoplastic including a thermoplastic resin selected from a group of thermoplastic resins consisting of nylon 6, nylon 66, nylon 46, aromatic polyamide, polyetherimide, polyethersulfone, polysulfone, polyphthalamide, polyphenylene sulfide, syndiotactic polystyrene, polyetherimide/silicone blend, liquid crystal polymer, polybutylene terephthalate, polyethylene terephthalate, cyclic thermoplastic, macrocyclic butylenes terephthalate, macrocyclic ethylene terephthalate, macrocyclic polycarbonate, thermoplastic urethane, polytetrafluoroethylene, polyvinylidene fluoride, polyetheretherketone and combinations thereof and a glass reinforcing element with a glass fiber weight fraction ranging from about 5 to about 90 weight percent where greater than about 5 weight percent of said glass fiber fraction has an original length to diameter ratio of greater than or equal to
 50. 4. The muffler assembly of claim 1, wherein said composite material is a mixture of between about 0 and about 90 weight percent polypropylene, between about 0 and about 90 weight percent polyethylene terephthalate and between about 10 and about 85 weight percent glass fibers.
 5. The muffler assembly of claim 1, wherein said composite material also includes some thermoset resin.
 6. The muffler assembly of claim 5, wherein said thermoset resin is selected from a group of thermoset resins consisting of unsaturated polyester, dicyclopentadiene, phenolic, phenol formaldehyde, novalac, resol, epoxy, vinyl ester, urethane and combinations thereof.
 7. The muffler assembly of claim 1, wherein said housing includes an inlet (20) and an outlet (22), a first heat sink (34) provided in said inlet and a second heat sink provided in said outlet.
 8. The muffler assembly of claim 1, wherein said housing includes an overmolded reinforcement.
 9. The muffler assembly of claim 8, wherein said overmolded reinforcement is an inlay (50) constructed from a material selected from a group consisting of nonwoven fiber mat, woven fiber mat, unidirectional fiber fabric, metal sheeting and combinations thereof.
 10. The muffler assembly of claim 9, where said inlay is made from a material selected from a group consisting of glass fibers, natural fibers, carbon fibers, mineral fibers, metallic fibers, aramid fibers and combinations thereof.
 11. The muffler assembly of claim 8, wherein said overmolded reinforcement is an overlay (52) providing impact resistance.
 12. The muffler assembly of claim 11, wherein said overlay is constructed from a material including metal sheeting, steel, aluminum, stainless steel, woven fiber mat, unwoven fiber mat, unidirectional fiber fabric and combinations thereof.
 13. The muffler assembly of claim 1, further including a baffle (46) in said housing.
 14. The muffler assembly of claim 1, further including one or several mounting brackets (38) carried by said housing.
 15. The muffler assembly of claim 1, further including an active sound control device (48) carried by said housing.
 16. The muffler assembly of claim 7, wherein said housing includes a first section (14), a second section (16) and a part line.
 17. The muffler assembly of claim 16, wherein said part line runs through said inlet and said outlet.
 18. The muffler assembly of claim 1, wherein at least a portion of said outer housing forms a vehicle component selected from a group consisting of a spare wheel well, an underbody shield, a fender, a wheel arch, a bumper, a running board, a rocker panel, a side fairing and an air dam.
 19. The muffler assembly of claim 1, further including an inner housing received in said housing, said inner housing being constructed from a second composite material comprising a thermoset resin and a reinforcement element. 